Dynamic Locomotion Control for Wheeled⁃legged Hybrid Platform in Complex Terrain

The dynamic and accurate tracking of the center-of-mass reference trajectory in complex terrain is crucial to ensure the stable execution of tasks for wheeled-legged hybrid platform. A dynamic locomotion control strategy is proposed to enhance the terrain adaptability and pose tracking capability of the platform. Taking into account terrain factors, a single rigid body dynamics model including wheel dynamics is established. The system dynamics model is then transformed into the standard form of state-space equations through an approximate simplification. Considering the coupled motion of the wheels and legs, a hybrid locomotion control method based on feedforward and feedback torques is introduced. The quadratic programming algorithm is used to solve the optimal ground reaction forces, and the Jacobian matrix is used to map these forces into the joints for feedforward torque generation. To address the external disturbances caused by the environment that may hinder the system's ability to perform optimization calculations in a short time frame, the joint torque feedback control is introduced to promptly correct the pose tracking errors. This enables the system to respond rapidly and accurately to the external disturbances, thus effectively improving its robustness and stability. Simulated results demonstrate that the proposed method significantly enhances the dynamic pose tracking accuracy of the platform in complex terrains, ensuring smooth platform operation. This method provides strong support for the engineering application of wheeled-legged hybrid platforms in complex terrains. © 2024 China Ordnance Industry Corporation. All rights reserved.